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Ordinary High Water Mark and Low Water Datum - Description

The U.S. Army Corps of Engineers Ordinary High Water Mark (OHWM) is a jurisdictional benchmark for administering its regulatory program in navigable waterways under Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act.  The OHWM is the line on the shore coincident with the elevation contour that represents the approximate location of the line on the shore established by fluctuations of water and indicated by physical characteristics such as shelving, destruction of terrestrial vegetation, presence of litter or debris, or changes in the character of soil.  The OHWM varies from lake to lake and within each of the connecting channels (e.g., St. Marys River, St. Clair River).  A table of OHWMs for several locations throughout the Great Lakes region can be found below.  The elevation reference system used to define Great Lakes water levels is the 1985 International Great Lakes Datum, which is commonly known by the acronym IGLD 1985.  

     The Detroit District’s Regulatory Office administers the Corps’ regulatory program in Michigan and the northern portion of Indiana.  Corps authorization is required for any fill, structures, or work waterward of the OHWM of one of the Great Lakes or a connecting channel.  Additionally, authorization is required for structures or work on the landward side of the OHWM if they affect the course, location, or condition of the waterbody so as to impact its navigable capacity.  If you anticipate any work as described above, you will need to request authorization for the work by completing an application found at the Detroit District's Regulatory Apply for a Permit web page and sending it to the Regulatory Office.  Please follow the application submittal procedures set forth in the applicant information section.  Plan view and cross-sectional view drawings, in 8 1/2 inch x 11 inch format, should accompany the application.  Drawings and a narrative on the form should specifically identify and describe all of the structures, work, and discharges which we regulate as described above, including temporary or construction measures.

     The state of Michigan has its own jurisdictional boundaries; please contact the Michigan Department of Environmental Quality (MDEQ) in Lansing at (517) 335-3471 for information on the States OHWM.   Additional information on the MDEQ’s Land and Water Management Division may be found at:  http://www.michigan.gov/deq/0,1607,7-135-3307_29692_24403---,00.html.  The Army Corps of Engineers and the MDEQ jointly administer the processing of permit applications for work in the Great Lakes and connecting channels but issue separate permits.  A Public Notice is issued on most permit applications above a certain threshold of size and scope.  Where possible, the Corps will issue a joint public notice with MDEQ to minimize duplication of effort. The Corps and the MDEQ conduct separate and independent application reviews. 

Ordinary High Water Mark and Low Water Datum - Table Of Values

Location Datum LWD (feet) OHWM (feet)  
Lake Superior IGLD 1985 601.1 603.1  
St. Marys River  
Brush Point IGLD 1985 601.0 603.0  
Upstream End- Soo Locks IGLD 1985 600.7 602.7  
Downstream @ Soo Locks IGLD 1985 578.8 582.8  
Mission Point IGLD 1985 578.7 582.7  
Neebish Island IGLD 1985 578.3 582.3  
Point Aux Frenes IGLD 1985 578.0 582.0  
De Tour Passage IGLD 1985 577.9 581.9  
Lake Michigan IGLD 1985 577.5 581.5  
Lake Huron IGLD 1985 577.5 581.5  
St. Clair River  
Blue Water Bridge IGLD 1985 576.9 580.9  
Black River- Mouth IGLD 1985 576.3 580.3  
Marysville IGLD 1985 575.7 579.7  
Stag Island- Downstream IGLD 1985 575.1 579.1  
St. Clair   IGLD 1985 574.7 578.7  
Det. Ed. N. / Marine City IGLD 1985 574.2 578.2  
Marine City IGLD 1985 573.9 577.9  
Roberts Island IGLD 1985 573.5 577.5  
Algonac IGLD 1985 573.1 577.1  
Sans Souci-Harsens Isl. IGLD 1985 572.9 576.9  
Harsens Isl. Dnstrm End IGLD 1985 572.7 576.7  
Lake St. Clair IGLD 1985 572.3 576.3  
Detroit River  
Grosse Point IGLD 1985 572.1 576.2  
Belle Isle- Upstream End IGLD 1985 571.9 576.0  
Belle Isle- Dnstrm End IGLD 1985 571.6 575.7  
Detroit @ Woodward Ave IGLD 1985 571.4 575.5  
Detroit @ Amb. Bridge IGLD 1985 571.3 575.4  
At River Rouge IGLD 1985 571.1 575.2  
Ecorse IGLD 1985 570.9 575.0  
Wyandotte IGLD 1985 570.6 574.7  
Riverview IGLD 1985 570.4 574.5  
Trenton IGLD 1985 570.0 574.1  
Gibraltar IGLD 1985 569.4 573.5  
Lake Erie IGLD 1985 569.2 573.4